Field
Embodiments described generally relate methods for separating particulates from aqueous suspensions with depressants. More particularly, such embodiments relate to methods for separating particulates from aqueous suspensions with depressants that include one or more polyamidoamine-epihalohydrin resins.
Description of the Related Art
Flotation, coagulation, flocculation, filtration, and sedimentation are widely used separation processes for the beneficiation of ores and other solids present as a component in a liquid suspension, dispersion, solution, slurry, or other mixture that includes particulates and a liquid. Adjuvants are often incorporated into the mixture to improve the selectivity of the process. For example, “collectors” can be used to chemically or physically adhere to solid particles and render the particles more hydrophobic and more likely to float. On the other hand, “depressants” can be used to chemically or physically adhere to solid particles and render the particles more hydrophilic and more likely to sink. In this manner, mixtures that include two (or more) different types of particulate material in a liquid can be separated by causing some material to float and other material to sink. For example, an aqueous suspension of kaolin clay, a material having a number of industrially significant applications, and iron and titanium oxides as impurities can be beneficiated by flotation of the impurities leaving a purified kaolin clay as a bottoms product.
The nature of both the desired and the unwanted components varies greatly in separation processes, which can be due, at least in part, to the differences in chemical composition of the materials, the types of any prior chemical treatment, and various processing steps used in generating the mixture, among other factors. Consequently, the number and types of depressants is correspondingly large. Various depressants are known in the art and include guar gum, sodium silicate, starch, tannins, dextrins, lignosulphonic acids, carboxymethyl cellulose, cyanide salts, and others. Despite the large offering of depressants known in the art, an adequate degree of refinement in many cases remains difficult to achieve.
There is a need, therefore, for improved depressants for use in separating particulates from aqueous suspensions.